Do have_submounts(), shrink_dcache_parent() and d_drop() atomically.

check_submounts_and_drop() can deal with negative dentries and
non-directories as well.

Non-directories can also be mounted on.  And just like directories we don't
want these to disappear with invalidation.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Do have_submounts(), shrink_dcache_parent() and d_drop() atomically.

check_submounts_and_drop() can deal with negative dentries as well.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: David Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We check submounts before doing d_drop() on a non-empty directory dentry in
NFS (have_submounts()), but we do not exclude a racing mount.  Nor do we
prevent mounts to be added to the disconnected subtree using relative paths
after the d_drop().

This patch fixes these issues by checking for unlinked (unhashed, non-root)
ancestors before proceeding with the mount.  This is done with rename
seqlock taken for write and with ->d_lock grabbed on each ancestor in turn,
including our dentry itself.  This ensures that the only one of
check_submounts_and_drop() or has_unlinked_ancestor() can succeed.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We check submounts before doing d_drop() on a non-empty directory dentry in
NFS (have_submounts()), but we do not exclude a racing mount.

 Process A: have_submounts() -> returns false
 Process B: mount() -> success
 Process A: d_drop()

This patch prepares the ground for the fix by doing the following
operations all under the same rename lock:

  have_submounts()
  shrink_dcache_parent()
  d_drop()

This is actually an optimization since have_submounts() and
shrink_dcache_parent() both traverse the same dentry tree separately.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: David Howells <dhowells@redhat.com>
CC: Steven Whitehouse <swhiteho@redhat.com>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This one replaces three instances open coded tree walking (have_submounts,
select_parent, d_genocide) with a common helper.

In addition to slightly reducing the kernel size, this simplifies the
callers and makes them less bug prone.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It shouldn't matter when we decrement the refcount during the walk as long
as we do it exactly once.

Restructure d_genocide() to do the killing on entering the dentry instead
of when leaving it.  This helps creating a common helper for tree walking.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Call generic_write_sync() from the deferred I/O completion handler if
O_DSYNC is set for a write request.  Also make sure various callers
don't call generic_write_sync if the direct I/O code returns
-EIOCBQUEUED.

Based on an earlier patch from Jan Kara <jack@suse.cz> with updates from
Jeff Moyer <jmoyer@redhat.com> and Darrick J. Wong <darrick.wong@oracle.com>.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add support to the core direct-io code to defer AIO completions to user
context using a workqueue.  This replaces opencoded and less efficient
code in XFS and ext4 (we save a memory allocation for each direct IO)
and will be needed to properly support O_(D)SYNC for AIO.

The communication between the filesystem and the direct I/O code requires
a new buffer head flag, which is a bit ugly but not avoidable until the
direct I/O code stops abusing the buffer_head structure for communicating
with the filesystems.

Currently this creates a per-superblock unbound workqueue for these
completions, which is taken from an earlier patch by Jan Kara.  I'm
not really convinced about this use and would prefer a "normal" global
workqueue with a high concurrency limit, but this needs further discussion.

JK: Fixed ext4 part, dynamic allocation of the workqueue.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Reviewed-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Christopher reported a regression where he was unable to unmount a NFS
filesystem where the root had gone stale. The problem is that
d_revalidate handles the root of the filesystem differently from other
dentries, but d_weak_revalidate does not. We could simply fix this by
making d_weak_revalidate return success on IS_ROOT dentries, but there
are cases where we do want to revalidate the root of the fs.

A umount is really a special case. We generally aren't interested in
anything but the dentry and vfsmount that's attached at that point. If
the inode turns out to be stale we just don't care since the intent is
to stop using it anyway.

Try to handle this situation better by treating umount as a special
case in the lookup code. Have it resolve the parent using normal
means, and then do a lookup of the final dentry without revalidating
it. In most cases, the final lookup will come out of the dcache, but
the case where there's a trailing symlink or !LAST_NORM entry on the
end complicates things a bit.

Cc: Neil Brown <neilb@suse.de>
Reported-by: NChristopher T Vogan <cvogan@us.ibm.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The d_prune dentry operation is used to notify filesystem when VFS
about to prune a hashed dentry from the dcache. There are three
code paths that prune dentries: shrink_dcache_for_umount_subtree(),
prune_dcache_sb() and d_prune_aliases(). For the d_prune_aliases()
case, VFS unhashes the dentry first, then call the d_prune dentry
operation. This confuses ceph_d_prune() (ceph uses the d_prune
dentry operation to maintain a flag indicating whether the complete
contents of a directory are in the dcache, pruning unhashed dentry
does not affect dir's completeness)

This patch fixes the issue by calling the d_prune dentry operation
in d_prune_aliases(), before unhashing the dentry. Also make VFS
only call the d_prune dentry operation for hashed dentry, to avoid
calling the d_prune dentry operation twice when dentry is pruned
by d_prune_aliases().
Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This moves __d_rcu_to_refcount() from <linux/dcache.h> into fs/namei.c
and re-implements it using the lockref infrastructure instead.  It also
adds a lot of comments about what is actually going on, because turning
a dentry that was looked up using RCU into a long-lived reference
counted entry is one of the more subtle parts of the rcu walk.

We also used to be _particularly_ subtle in unlazy_walk() where we
re-validate both the dentry and its parent using the same sequence
count.  We used to do it by nesting the locks and then verifying the
sequence count just once.

That was silly, because nested locking is expensive, but the sequence
count check is not.  So this just re-validates the dentry and the parent
separately, avoiding the nested locking, and making the lockref lookup
possible.
Acked-by: NWaiman Long <waiman.long@hp.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A valid parent pointer is always going to have a non-zero reference
count, but if we look up the parent optimistically without locking, we
have to protect against the (very unlikely) race against renaming
changing the parent from under us.

We do that by using lockref_get_not_zero(), and then re-checking the
parent pointer after getting a valid reference.

[ This is a re-implementation of a chunk from the original patch by
  Waiman Long: "dcache: Enable lockless update of dentry's refcount".
  I've completely rewritten the patch-series and split it up, but I'm
  attributing this part to Waiman as it's close enough to his earlier
  patch  - Linus ]
Signed-off-by: NWaiman Long <Waiman.Long@hp.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Previous attempt to fix was b042e474

Suggested use of is_power_of_2() was bogus because is_power_of_2(0) is
false (documented behaviour).
Signed-off-by: NMaxime Bizon <mbizon@freebox.fr>
Acked-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

While using pacemaker/corosync, the node numbers are generated using IP
address as opposed to serial node number generation.  This may not fit
in a 8-byte string.  Use a bigger string to print the complete node
number.
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This just replaces the dentry count/lock combination with the lockref
structure that contains both a count and a spinlock, and does the
mechanical conversion to use the lockref infrastructure.

There are no semantic changes here, it's purely syntactic.  The
reference lockref implementation uses the spinlock exactly the same way
that the old dcache code did, and the bulk of this patch is just
expanding the internal "d_count" use in the dcache code to use
"d_lockref.count" instead.

This is purely preparation for the real change to make the reference
count updates be lockless during the 3.12 merge window.

[ As with the previous commit, this is a rewritten version of a concept
  originally from Waiman, so credit goes to him, blame for any errors
  goes to me.

  Waiman's patch had some semantic differences for taking advantage of
  the lockless update in dget_parent(), while this patch is
  intentionally a pure search-and-replace change with no semantic
  changes.     - Linus ]
Signed-off-by: NWaiman Long <Waiman.Long@hp.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's always been a hassle that if an external journal's
device number changes, the filesystem won't mount.
And since boot-time enumeration can change, device number
changes aren't unusual.

The current mechanism to update the journal location is by
passing in a mount option w/ a new devnum, but that's a hassle;
it's a manual approach, fixing things after the fact.

Adding a mount option, "-o journal_path=/dev/$DEVICE" would
help, since then we can do i.e.

# mount -o journal_path=/dev/disk/by-label/$JOURNAL_LABEL ...

and it'll mount even if the devnum has changed, as shown here:

# losetup /dev/loop0 journalfile
# mke2fs -L mylabel-journal -O journal_dev /dev/loop0 
# mkfs.ext4 -L mylabel -J device=/dev/loop0 /dev/sdb1

Change the journal device number:

# losetup -d /dev/loop0
# losetup /dev/loop1 journalfile 

And today it will fail:

# mount /dev/sdb1 /mnt/test
mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

# dmesg | tail -n 1
[17343.240702] EXT4-fs (sdb1): error: couldn't read superblock of external journal

But with this new mount option, we can specify the new path:

# mount -o journal_path=/dev/loop1 /dev/sdb1 /mnt/test
#

(which does update the encoded device number, incidentally):

# umount /dev/sdb1
# dumpe2fs -h /dev/sdb1 | grep "Journal device"
dumpe2fs 1.41.12 (17-May-2010)
Journal device:	          0x0701

But best of all we can just always mount by journal-path, and
it'll always work:

# mount -o journal_path=/dev/disk/by-label/mylabel-journal /dev/sdb1 /mnt/test
#

So the journal_path option can be specified in fstab, and as long as
the disk is available somewhere, and findable by label (or by UUID),
we can mount.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>

If the group descriptor fails validation, mark the whole blockgroup
corrupt so that the inode/block allocators skip this group.  The
previous approach takes the risk of writing to a damaged group
descriptor; hopefully it was never the case that the [ib]bitmap fields
pointed to another valid block and got dirtied, since the memset would
fill the page with 1s.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If we detect either a discrepancy between the inode bitmap and the
inode counts or the inode bitmap fails to pass validation checks, mark
the block group corrupt and refuse to allocate or deallocate inodes
from the group.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

When we notice a block-bitmap corruption (because of device failure or
something else), we should mark this group as corrupt and prevent
further block allocations/deallocations from it. Currently, we end up
generating one error message for every block in the bitmap. This
potentially could make the system unstable as noticed in some
bugs. With this patch, the error will be printed only the first time
and mark the entire block group as corrupted. This prevents future
access allocations/deallocations from it.

Also tested by corrupting the block
bitmap and forcefully introducing the mb_free_blocks error:
(1) create a largefile (2Gb)
$ dd if=/dev/zero of=largefile oflag=direct bs=10485760 count=200
(2) umount filesystem. use dumpe2fs to see which block-bitmaps
are in use by largefile and note their block numbers
(3) use dd to zero-out the used block bitmaps
$ dd if=/dev/zero of=/dev/hdc4 bs=4096 seek=14 count=8 oflag=direct
(4) mount the FS and delete the largefile.
(5) recreate the largefile. verify that the new largefile does not
get any blocks from the groups marked as bad.
Without the patch, we will see mb_free_blocks error for each bit in
each zero'ed out bitmap at (4). With the patch, we only see the error
once per blockgroup:
[  309.706803] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 15: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.720824] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 14: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.732858] EXT4-fs error (device sdb4) in ext4_free_blocks:4802: IO failure
[  309.748321] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 13: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.760331] EXT4-fs error (device sdb4) in ext4_free_blocks:4802: IO failure
[  309.769695] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 12: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.781721] EXT4-fs error (device sdb4) in ext4_free_blocks:4802: IO failure
[  309.798166] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 11: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.810184] EXT4-fs error (device sdb4) in ext4_free_blocks:4802: IO failure
[  309.819532] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 10: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.

Google-Bug-Id: 7258357

[darrick.wong@oracle.com]
Further modifications (by Darrick) to make more obvious that this corruption
bit applies to blocks only.  Set the corruption flag if the block group bitmap
verification fails.

Original-author: Aditya Kali <adityakali@google.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The block_group parameter to ext4_validate_block_bitmap is both used
as a ext4_group_t inside the function and the same type is passed in
by all callers.  We might as well use the typedef consistently instead
of open-coding the 'unsigned int'.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The block bitmap verification code assumes that calling ext4_error()
either panics the system or makes the fs readonly.  However, this is
not always true: when 'errors=continue' is specified, an error is
printed but we don't return any indication of error to the caller,
which is (probably) the block allocator, which pretends that the crud
we read in off the disk is a usable bitmap.  Yuck.

A block bitmap that fails the check should at least return no bitmap
to the caller.  The block allocator should be told to go look in a
different group, but that's a separate issue.

The easiest way to reproduce this is to modify bg_block_bitmap (on a
^flex_bg fs) to point to a block outside the block group; or you can
create a metadata_csum filesystem and zero out the block bitmaps.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

In the jbd2 checksumming code, explicitly declare separate variables with
endianness information so that we don't get confused and screw things up again.
Also fixes sparse warnings.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

After applied the commit (4a092d73), we have reduced the number of
source files that need to #include ext4_extents.h.  But we can do
better.

This commit defines ext4_zeroout_es() in extents.c and move
EXT_MAX_BLOCKS into ext4.h in order not to include ext4_extents.h in
indirect.c and ioctl.c.  Meanwhile we just need to include this file in
extent_status.c when ES_AGGRESSIVE_TEST is defined.  Otherwise, this
commit removes a duplicated declaration in trace/events/ext4.h.

After applied this patch, we just need to include ext4_extents.h file
in {super,migrate,move_extents,extents}.c, and it is easy for us to
define a new extent disk layout.
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NAnatol Pomozov <anatol.pomozov@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Use wait_for_stable_page() instead of wait_on_page_writeback()
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>

If ext_debugging is enabled and path[depth].p_ext is NULL, len
and lblock are printed non initialized
Signed-off-by: NAndi Shyti <andi@etezian.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This reverts commit bb2314b4.

It wasn't necessarily wrong per se, but we're still busily discussing
the exact details of this all, so I'm going to revert it for now.

It's true that you can already do flink() through /proc and that flink()
isn't new.  But as Brad Spengler points out, some secure environments do
not mount proc, and flink adds a new interface that can avoid path
lookup of the source for those kinds of environments.

We may re-do this (and even mark it for stable backporting back in 3.11
and possibly earlier) once the whole discussion about the interface is done.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This should actually be returning an ERR_PTR on error instead of NULL.
That was how it was designed and all the callers expect it.

[AV: actually, that's what "VFS: Make clone_mnt()/copy_tree()/collect_mounts()
return errors" missed - originally collect_mounts() was expected to return
NULL on failure]

Cc: <stable@vger.kernel.org> # 3.10+
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

iget_locked() returns a NULL on error, it doesn't return an ERR_PTR.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The iget_locked() function returns NULL on error and never an ERR_PTR.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

proc_readfd_common() does dir_emit_dots() twice in a row,
we need to do this only once.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

dynamic_dname() is both too much and too little for those - the
output may be well in excess of 64 bytes dynamic_dname() assumes
to be enough (thanks to ashmem feeding really long names to
shmem_file_setup()) and vsnprintf() is an overkill for those
guys.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Fix the issue with improper counting number of flying bio requests for
BIO_EOPNOTSUPP error detection case.

The sb_nbio must be incremented exactly the same number of times as
complete() function was called (or will be called) because
nilfs_segbuf_wait() will call wail_for_completion() for the number of
times set to sb_nbio:

  do {
      wait_for_completion(&segbuf->sb_bio_event);
  } while (--segbuf->sb_nbio > 0);

Two functions complete() and wait_for_completion() must be called the
same number of times for the same sb_bio_event.  Otherwise,
wait_for_completion() will hang or leak.
Signed-off-by: NVyacheslav Dubeyko <slava@dubeyko.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove double call of bio_put() in nilfs_end_bio_write() for the case of
BIO_EOPNOTSUPP error detection.  The issue was found by Dan Carpenter
and he suggests first version of the fix too.
Signed-off-by: NVyacheslav Dubeyko <slava@dubeyko.com>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>